1. Field of the Invention
The invention relates to a suture sleeve for securing a medical implantable lead in position in relation to a human or animal body, of the type having a tubular body of a resilient material defining a through bore in the longitudinal direction of the suture sleeve and being formed with one or more longitudinal spaced, circumferential suture grooves on the outside and two or more grip enhancing projections around the inner circumference of the through bore in at least an area radially inward of a suture groove.
The invention also relates to a method for manufacturing of a suture sleeve.
2. Description of the Prior Art
Medical implantable leads are used for various purposes in order to connect the inner of a human or animal body with the outside or a device arranged subcutaneously. As examples of such leads can be mentioned electrical leads for monitoring and/or controlling of the function of a heart by means of a pacemaker or a cardiac defibrillator arranged subcutaneously, or a flexible tube for draining of liquid from the body or dispensing of drugs to a specific organ inside the body.
When implanting a lead into a body, it is common practice to arrange a suture sleeve around the lead which is formed as a tube of a resilient material and provided with one or more circumferential suture grooves on the outer surface. During implantation, the suture sleeve is positioned at an incision through a vein or some other kind of tissue formation and by means of a suture wire, positioned around tissue and the suture sleeve in the area of the suture groove, the suture sleeve can be fixated in relation to the tissue. At the same time the incision can be sealed by tying the tissue around the incision to the suture sleeve, and by tightening the suture wire the lead can be fixated to the suture sleeve by clamping of the inner surface of the bore through the suture sleeve against the outer surface of the lead due to the tightening action of the suture wire around the lead.
However, due to small lead dimensions and glossy outer surfaces of the leads having a low coefficient of friction, it can sometimes be difficult to fixate the lead properly inside the suture sleeve, since the suture wire cannot be tightened excessively due to the risk of cutting through tissue as well as the suture sleeve itself. A lead which is not properly fixated to the tissue may accidentally be pulled out, which can be devastating for its function since its inner end normally is in engagement with an organ to be controlled, treated or monitored. To overcome this problem, it is known in the art to arrange projections and the like on the interior sleeve surface at least in a region radially inward of each suture groove. In this way the gripping force, between the suture sleeve and the lead can be increased. Examples of such designs are disclosed e.g. in U.S. Pat. No. 5,129,405, US 2004/0254623 and US 2006/0264803. However, the effect, in terms of increased gripping force, of the suture sleeves disclosed according to the prior art, is not quite satisfactory.